The invention discloses a method for quickly determining water content of feather down by adopting a Near Infrared Spectrum (NIR), and belongs to the field of analytical testing. The method comprises the following steps: step 1, collecting feather down samples and measuring the water contents thereof; step 2, acquiring the water contents of the feather down samples and removing abnormal samples, dividing the removed abnormal samples into modeling samples and prediction samples, then adopting partial least squares to establish a calibration model and adopting the prediction samples to perform external inspection on the model, so as to obtain a quantitative model; and besides, calculating the samples to be measured through the quantitative model to obtain the water contents of feather down samples to be measured. Compared with a conventional oven method, the method for quickly determining water content of the feather down by adopting the Near Infrared Spectrum (NIR) provided by the invention is simple to operate, low in cost, quick in measurement, and stable in data, realizes quick determination of water content of feather down, and provides high convenience for feather down manufacturing enterprises, import and export trade and testing laboratories.